Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/16—Ethylene-propylene or ethylene-propylene-diene copolymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L7/00—Compositions of natural rubber
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons
  • C08L9/06—Copolymers with styrene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L91/00—Compositions of oils, fats or waxes; Compositions of derivatives thereof
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L91/00—Compositions of oils, fats or waxes; Compositions of derivatives thereof
  • C08L91/06—Waxes
  • C08L91/08—Mineral waxes

Definitions

• the invention relates to the use of base oils as extender oils in elastomer production.
• the invention relates to the use of gas-to-liquid (GTL) derived base oils as elastomer extender oils.
• GTL gas-to-liquid
• High viscosity base oils derived from GTL synthesis often show a hazy appearance that is typically due to the presence of a small quantity of microcrystalline wax particles.
• elastomer extender oils There has been a desire in the art to assume that such oils are unsuitable some applications including use as elastomer extender oils.
• this conventional view is particularly entrenched with regards to oils with a high viscosity and high pour point.
• US2009/203835 describes a process to prepare a blend of a mineral derived residual and de-asphalted oil component, the blend as obtainable, a cylinder oil composition comprising said oil blend, and to the use of the oil blend as a process oil for various processes.
• WO2010/125144 describes functional fluid compositions which are useful as hydraulic fluids and shock absorber fluids and which have improved seal swell properties.
• WO2010/094681 describes the use of a lubricating composition comprising a Fischer-Tropsch derived base oil and one or more additives for particular use in the crankcase of an internal combustion engine, in particular a diesel engines such as a heavy duty diesel engine.
• WO-A-2005/063940 describes a process for the preparation of a Fischer-Tropsch wax derived haze free base oil having a kinematic viscosity at 100° C. of greater than 10 cSt.
• WO-A-2005/063940 includes additional processing intended to reduce the wax content of a Fischer-Tropsch synthesis product that has been subjected to hydroisomerisation (catalytic cracking) and distillation to remove lighter fuel products by undertaking additional hydroisomerisation and solvent dewaxing steps.
• WO-A-03033622 describes a process wherein a haze free base oil is prepared from a Fischer-Tropsch product by removing the heaviest fraction, containing the haze precursors, by a deep-cut distillation performed at a cut-off temperature of between 1150 and 1350° F. (621-732° C.). This is not only a technically difficult distillation step it also removes valuable heavy base oil molecules in addition to the haze precursors.
• a disadvantage of the processes described in the art is that the processing of Fischer Tropsch synthesis products is extended considerably in order to produce conventional haze-free clear and bright base oils that are regarded as suitable for use, for example, as elastomer extender oils and in particular as extender oils for synthetic rubbers.
• the cost of production of GTL-derived base oils can be relatively high rendering them less suitable for use as extender oils compared to mineral oil equivalents.
• Elastomer extender oil compositions are added to natural and synthetic elastomers, including rubbers, for a number of reasons, for example to reduce the mixing temperature required during processing and to prevent the scorching of the rubber polymer when it is being ground, to decrease the viscosity of the rubber to improve the general workability of the rubber compound, to aid in the dispersion of fillers, as well as to modify the physical properties of the rubber compound.
• GTL-derived base oils comprising haze components can be used as extender oils in production of elastomers without the need to first remove the haze components.
• elastomers comprising the GTL-derived base oils as extenders, and that have not been subjected to haze-removal are not inferior to comparative elastomers comprising bright stock base oils and is some cases will perform better.
• the invention provides an elastomer composition that comprises GTL-derived base oil, which GTL-derived base oil has not been subjected to a process for the removal of haze components.
• the GTL-derived base oil comprises a Fischer Tropsch synthesis product.
• an elastomer composition comprising at least one elastomer component, and a GTL-derived extender oil, wherein the GTL-derived extender oil has not been treated to remove haze components.
• the base oil comprises a wax component that is present in the range of from at least about 0.001 wt % to at most about 5 wt %, typically at most about 1 wt %, suitably at most no more than 0.1 wt % based on the total weight of the base oil.
• the GTL-derived extender oil comprises a GTL-derived base oil that includes at least some paraffinic wax content—i.e. sufficient microcrystalline wax content to render the appearance of the base oil at least partially opaque (hazy) at room temperature and pressure.
• an elastomer composition comprising:
• a further aspect of the invention provides for a process for the manufacture of an elastomer composition
• a process for the manufacture of an elastomer composition comprising combining at least one elastomer, elastomer component, or a mixture thereof with an extender oil, the extender oil comprising a GTL-derived base oil that includes a haze-causing paraffinic microcrystalline wax content, the extender oil present in the range of from at least about 0.1 wt % to at most about 50 wt % based on the total weight of the elastomer composition, suitably at least about 5 wt % and at most around 20 wt %, more suitably up to at least 15 wt %.
• the extender oil may be included at a relative amount of at least 0.2 to at most 100 parts per hundred of rubber (PHR).
• the GTL-derived base oil as used in the invention can be a Fischer-Tropsch synthesis product obtained by well-known processes, for example the so-called Sasol process, the Shell Middle Distillate Process or by the ExxonMobil “AGC-21” process. These and other processes are for example described in more detail in EP-A-776959, EP-A-668342, U.S. Pat. No. 4,943,672, U.S. Pat. No. 5,059,299, WO-A-9934917 and WO-A-9920720.
• the Fischer-Tropsch synthesis product comprises at least 30 wt %, preferably at least 50 wt %, and more preferably at least 55 wt % of compounds having at least 30 carbon atoms. Furthermore the weight ratio of compounds having at least 60 or more carbon atoms and compounds having at least 30 carbon atoms of the Fischer-Tropsch product is at least 0.2, preferably at least 0.4 and more preferably at least 0.55.
• the Fischer-Tropsch product comprises a C 20 + fraction having an ASF-alpha value (Anderson-Schulz-Flory chain growth factor) of at least 0.925, preferably at least 0.935, more preferably at least 0.945, even more preferably at least 0.955.
• ASF-alpha value Anderson-Schulz-Flory chain growth factor
• the initial boiling point of the Fischer-Tropsch product may range up to 400° C., but is preferably below 200° C.
• any compounds having 4 or less carbon atoms and any compounds having a boiling point in that range are separated from a Fischer-Tropsch synthesis product before the Fischer-Tropsch synthesis product is used in said hydroisomerisation step.
• Such a Fischer-Tropsch product can be obtained by any process, which yields a relatively heavy Fischer-Tropsch product. However, not all Fischer-Tropsch processes yield such a heavy product.
• An example of a suitable Fischer-Tropsch process is described in WO-A-9934917 and in AU-A-698392. These processes may yield a Fischer-Tropsch product as described above.
• the Fischer-Tropsch product will contain no or very little sulphur and nitrogen containing compounds. This is typical for a product derived from a Fischer-Tropsch reaction, which uses synthesis gas containing almost no impurities. Sulphur and nitrogen levels will generally be below the detection limits, which are currently 5 ppm for sulphur and 1 ppm for nitrogen.
• the waxy synthesis product of Fischer Tropsch reaction is typically subjected to a hydrocracking/hydroisomerisation reaction that is suitably performed in the presence of hydrogen and a catalyst, which catalyst can be chosen from those known to one skilled in the art as being suitable for this reaction.
• Catalysts for use in the hydroisomerisation typically comprise an acidic functionality and a hydrogenation/dehydrogenation functionality.
• Preferred acidic functionality's are refractory metal oxide carriers.
• Suitable carrier materials include silica, alumina, silica-alumina, zirconia, titania and mixtures thereof.
• Preferred carrier materials for inclusion in the catalyst for use in the process of this invention are silica, alumina and silica-alumina.
• a particularly preferred catalyst comprises platinum supported on a silica-alumina carrier.
• the catalyst does not contain a halogen compound, such as for example fluorine, because the use of such catalysts require special operating conditions and involve environmental problems.
• a halogen compound such as for example fluorine
• Preferred hydrogenation/dehydrogenation functionality's are Group VIIIB metals, for example cobalt, nickel, palladium and platinum and more preferably platinum.
• the catalyst may comprise the hydrogenation/dehydrogenation active component in an amount of from 0.005 to 5 parts by weight, preferably from 0.02 to 2 parts by weight, per 100 parts by weight of carrier material.
• nickel or cobalt a higher content will be present, optionally nickel is used in combination with copper.
• a particularly preferred catalyst for use in the hydroconversion stage comprises platinum in an amount in the range of from 0.05 to 2 parts by weight, more preferably from 0.1 to 1 parts by weight, per 100 parts by weight of carrier material.
• the catalyst may also comprise a binder to enhance the strength of the catalyst.
• the binder can be non-acidic. Examples are clays and other binders known to one skilled in the art.
• the feed is contacted with hydrogen in the presence of the catalyst at elevated temperature and pressure.
• the temperatures typically will be in the range of from 175 to 380° C., preferably higher than 250° C. and more preferably from 300 to 370° C.
• the pressure will typically be in the range of from 10 to 250 bar and preferably between 20 and 80 bar.
• Hydrogen may be supplied at a gas hourly space velocity of from 100 to 10000 Nl/1/hr, preferably from 500 to 5000 Nl/l/hr.
• the hydrocarbon feed may be provided at a weight hourly space velocity of from 0.1 to 5 kg/l/hr, preferably higher than 0.5 kg/l/hr and more preferably lower than 2 kg/l/hr.
• the ratio of hydrogen to hydrocarbon feed may range from 100 to 5000 Nl/kg and is preferably from 250 to 2500 Nl/kg.
• the conversion in the hydroisomerisation as defined as the weight percentage of the feed boiling above 370° C. which reacts per pass to a fraction boiling below 370° C. is at least 20 wt %, preferably at least 25 wt %, but preferably not more than 80 wt %, more preferably not more than 70 wt %.
• the feed as used above in the definition is the total hydrocarbon feed fed to the hydroisomerisation, thus also any optional recycle step.
• One or more distillate separations may be performed on the effluent of the hydroisomerisation reaction to obtain at least one middle distillate fuel fraction and heavier hydrocarbon bottoms referred to as the residue.
• the residue as obtained in such a distillation is optionally subjected to a further distillation performed at near vacuum conditions.
• This bottom product or residue preferably boils for at least 95 wt % above 370° C.
• the vacuum distillation is suitably performed at a pressure of between at least 0.001 and at most 0.1 bara.
• the residue is obtained as the bottom product of such a vacuum distillation.
• the 10 wt % recovery boiling point of the residue is typically between 350 and 550° C.
• the wax content of the residue is low to start with although it is sufficient to impart a hazy appearance to base oils derived from the residue.
• the wax content of the residue can be measured according to the following procedure. 1 weight part of the to be measured oil fraction is diluted with 4 parts of a (50/50 vol/vol) mixture of methyl ethyl ketone and toluene, which is subsequently cooled to ⁇ 20° C. in a refrigerator. The mixture is subsequently filtered at ⁇ 20° C. The wax is thoroughly washed with cold solvent, removed from the filter, dried and weighed. If reference is made to a wax content as a wt % value is meant the percentage of the total oil which is made up of wax.
• the residue would be processed further using any suitable hydroconversion process, which is intended to further reduce the wax content of the residue.
• the hydroconversion process would typically include special dewaxing catalysts that comprise a molecular sieve optionally in combination with a metal having a hydrogenation function.
• a minimal amount of wax is required in order to operate additional solvent dewaxing steps in an optimal manner.
• Solvent dewaxing is well known to those skilled in the art and involves admixture of one or more solvents and/or wax precipitating agents with the base oil precursor fraction and cooling the mixture to a temperature in the range of from ⁇ 10° C. to ⁇ 40° C., to separate the wax from the oil.
• the oil containing the wax is usually then filtered so as to produce a fully de-hazed final bright stock oil.
• suitable solvent dewaxing processes are described in Lubricant Base Oil and Wax Processing, Avilino Sequeira, Jr, Marcel Dekker Inc., New York, 1994, Chapter 7.
• GTL base oils i.e. base oils obtained from a Fischer Tropsch synthesis reaction
• haze causing components such as wax
• the haze causing components do not contribute substantially to a reduction of performance of base oils in applications such as for use as elastomer extender oils
• Haze causing components present within the base oils utilised in the present invention typically comprise a soft microcrystalline wax component that has a congealing point as determined by ASTM D 938 of between 85 and 120° C. and more preferably between 95 and 120° C. and a PEN at 43° C. as determined by IP 376 (determination of needle penetration of petroleum wax) of more than 0.8 mm and preferably more than 1 mm.
• the wax is further characterized in that it is predominantly paraffinic in nature and preferably comprises less than 1 wt % aromatic compounds and less than 10 wt % naphthenic compounds, more preferably less than 5 wt % naphthenic compounds.
• the mol percentage of branched paraffins in the wax is typically above 33 and more preferably above 45 and below 80 mol % as determined by C 13 NMR.
• This method determines an average molecular weight for the wax and subsequently determines the mol percentage of molecules having a methyl branch, the mol percentage of molecules having an ethyl branch, the mol percentage of molecules having a C 3 branch and the mol percentage having a C 4+ branch, under the assumption that each molecule does not have more than one branch.
• the mol % of branched paraffins is the total of these individual percentages.
• This method calculated the mol % in the wax of an average molecule having only one branch. In reality paraffin molecules having more than one branch may be present. Thus the content of branched paraffins determined by different method may result in a different value.
• haze-free base oils including bright stock oils, will usually have a kinematic viscosity at 100° C. of above 10 cSt which viscosity may range up to 40 cSt and above. Kinematic viscosity may be determined at 40 and 100° C. by standard methods including ASTM D445. The pour point is typically below ⁇ 5° C. and even more usually below ⁇ 21° C. The viscosity index is suitably above 120 and usually above 130.
• a haze free base oil can also be determined by its cloud point: as determined by ASTM D2500 of near the pour point and below 0° C., usually below ⁇ 10° C.
• Hazy GTL base oils of the present invention are defined as a Fischer Tropsch derived oil having a carbon chain length of typically greater than C 20+ and comprising a wax component of between at least around 0.001 wt % and at most around 5 wt %, typically at most no more than around 1% wt, suitably at most no more than 0.1 wt %.
• the hazy GTL-derived base oils of the invention are visibly at least partially or completely opaque at ambient temperature.
• the base oils utilised in the present invention comprise sufficient additional heavy components (such as wax) to impart a visible haze to the appearance of the oil.
• the base oils of the present invention would not be described conventionally as ‘clear’ or ‘bright’.
• Hazy base oils of the invention will typically be rendered clear and bright upon heating to temperatures in excess of 50° C.
• the GTL derived base oil is defined as a heavy base oil component comprising carbons of up to around C 40 , typically in the range of between at least C 20 and at most C 40 , as well as haze causing components.
• the base oil of the invention typically has a kinematic viscosity at 40° C. in excess of at least 80 mm 2 /s, suitably in excess of at least 100 mm 2 /s.
• the base oil of the invention typically has a kinematic viscosity at 100° C. in excess of at least of at least 10 mm 2 /s, suitably in excess of at least 15 mm 2 /s, optionally up to around 35 mm 2 /s.
• the invention provides advantageously for the use of so-called extra-heavy hazy base oils as extender oils for elastomer compositions.
• a GTL derived hazy heavy base oil suitable for use as a elastomer, synthetic rubber extender oil is characterised by a kinematic viscosity at 40° C. of 151 mm 2 /s and at 100° C. of 19 mm 2 /s; a cold pour point of ⁇ 24° C. and a density at 15° C. of around 837 kg/m 3 .
• the elastomer is a rubber, optionally selected from elastomers comprising any of the following, including combinations—i.e. copolymers—thereof:
• the elastomer in use is a thermoplastic elastomer (TPE) or an ethylene propylene diene monomer (EPDM) rubber.
• TPEs include styrenic block copolymers, polyolefin blends, elastomeric alloys, thermoplastic polyurethanes, thermoplastic copolyesters and thermoplastic polyamides.
• compounding agents used in the rubber industry such as tackifiers, vulcanization controlling agents, high loss-providing agents and low loss-providing agents, may also be optionally included in the rubber composition.
• reinforcing agents are carbon black and silica.
• cross-linking agents and cross-linking auxiliaries are organic peroxides, sulfur and organic sulfur compounds as cross-linking agents, and thiazole compounds and guanidine compounds as the cross-linking auxiliaries.
• inorganic fillers are calcium carbonate, magnesium carbonate, clay, alumina, aluminium hydroxide, mica and the like. Any suitable waxes and/or antioxidants may be incorporated in order to prevent or reduce degradation.
• the method of making the elastomer composition of the present invention comprises the blending of the components of the elastomer composition, components a) to f), in any order.
• the conditions used in the preparation of the elastomer and rubber compositions of the present invention are known to those skilled in the art.
• a specific embodiment of the present invention provides a process for the manufacture of an elastomer composition
• a process for the manufacture of an elastomer composition comprising combining at least one elastomer, elastomer component, or a mixture thereof with an extender oil, the extender oil comprising a GTL-derived base oil that includes a paraffinic wax content, the extender oil present in the range of from at least about 0.1 wt % to at most about 50 wt % based on the total weight of the elastomer composition (equivalent to 0.2 to 100 parts per hundred rubber); and wherein the base oil includes a microcrystalline wax content of between at least about 0.001 wt % and at most about 5 wt %.
• a specific embodiment of the invention also provides for a process for the manufacture of an elastomer product comprising obtaining an elastomer composition according to the process described above, and forming a product from the elastomer composition.
• the elastomers of the invention may be formed, moulded, rolled, pressed or cut by conventional methods in order to produce an elastomer containing product.
• the elastomers produced according to the methods of the invention may be formed into a wide variety of products, as will be appreciated by the skilled person including—but not limited to—tyres, elastomer sheeting, washers, o-rings, construction materials, fabrics, coatings, seals, tubing, electrical insulation, membranes, mechanical products, dampers, and clothing.
• a GTL-derived hazy heavy base oil of the invention (denoted as oil 4) was used in the production of TPE and EPDM synthetic rubber compositions as described below.
• oil 4 A GTL-derived hazy heavy base oil of the invention (denoted as oil 4) was used in the production of TPE and EPDM synthetic rubber compositions as described below.
• three bright stock base oils were also used (see Table 1).
• the first comparison oil (oil 1) is a GTL-derived base oil which has been subjected to dewaxing in order to render a clear and bright GTL derived base oil.
• Two technical white oils of mineral origin (oils 2 and 3) have been used.
• oil 3 was used for comparison as it displays very similar kinematic viscosity at 100° C. to that of oil 4.
• oils 1, 2 and 4 (40 g in a pour point method glass and covered by a watch glass) were graded for their apparent colour according to ASTM 1500 and then maintained at a temperature of 150° C. for 20 hours. The results of the test are shown in Table 2.
• the GTL-derived oils 1 and 4 did not show any appreciative change in colour, whereas mineral derived oil 2 showed a considerable change in colour. This indicates that mineral derived oils are less suited to inclusion in elastomer compositions where temperature stability of colour is an important factor.
• TPE compositions were prepared comprising the hazy base oil of the invention and the comparative oils.
• the TPE formulations were of conventional type and are set out in Table 3.
• the quantities of the components are given as per hundred rubber (PHR) values which is conventional in the art (see page 2, Part 1.2, Rubber Technology: Compounding and Testing for Performance , R. A. Annicelli, Hanser Verlag, 2001) with the total value of the elastomer (rubber) being the sum total of natural and styrene butadiene rubber (SBR) components shown.
• PHR per hundred rubber
• SBR styrene butadiene rubber
• the TPE elastomers prepared as Examples 1-4 were subjected to a variety of industry standard tests for hardness, tear strength and resistance and deformation as set out in Table 4. Unexpectedly, the TPE elastomer of the invention (as shown in Example 4) performs comparatively with the other elastomers of Examples 1-3 which comprise conventional clear and bright extender oils. In fact in some tests it can be seen that the elastomer of Example 4 even outperforms the conventional elastomers.
• EPDM compositions were prepared comprising the hazy base oil of the invention and the comparative oils.
• the EPDM formulations were of conventional type and are set out in Table 5.
• the quantities of the components are given as parts per hundred rubber (PHR) values, with the total value of the elastomer (rubber) being the sum total of ethylene propylene diene terpolymer and ethylene propylene diene rubber with ethylidene norbornene as diene component.
• PHR parts per hundred rubber
• Dicyclopentadiene or vinyl nobernene are also suitable diene components for EPDM rubbers in general.
• the EPDM elastomers prepared as Examples 5-8 were subjected to a variety of industry standard tests for hardness, tear strength and resistance and deformation as set out in Table 6. Compared to the TPE testing regimen set out in Table 4, additional high temperature immersion tests were also carried out on the EPDM polymers of Examples 5-8. Unexpectedly, the EPDM elastomer of the invention (as shown in Example 8) performs comparatively with the other elastomers of Examples 5-7 which comprise conventional clear and bright extender oils. In fact in some tests it can be seen that the elastomer of Example 8 even outperforms the conventional elastomers.

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• 2012
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